Sledge hammer or jack hammer to destroy it.
Build nice new wood stairs, bolted to the porch, with some washers as spacers so the gap between can breathe.
But first, prop up that sagging porch.
The whole thing sags like an old swayback mule, put some stacked patio blocks or deck blocks on a patio block down under it, dug down onto firmer soil.
Jack it up for a few weeks or months until it returns to a decent level besides sag city.
Then bang in some 4 x 4 pieces to replace the jacks.